Fluorescent tubes that are designed to mimic the behavior of daylight (such as the D50 standard for daylight simulation) follow the requirements of international specifications for lighting, for example ISO 3664. These standards were optimized for the requirements of hard copy proofing. This means that different print media such as an ink jet proof and a press sheet must match numerically and visually under a daylight simulator, if calculations using the D50 standard illumination predict that the colors will match.
The standards are less rigorous with regard to the absolute simulation of D50 for a D50 simulator. For example, a solid yellow color printed with an ink jet printer and printing press might shift by 5 ΔE in the direction of green for a particular D50 simulator. That lighting may still be considered an acceptable approximation to D50 as long as the difference between the two colors is small.
This qualification of tubes based on relative versus absolute simulation of D50 is problematic when one attempts to match a display to a printed image viewed in a D50 simulator. In this case, the display may be calibrated and profiled in order to simulate colors viewed with theoretical D50. The ΔE match to D50 can be made very accurate in an absolute sense. If the D50 simulator in fact is significantly different spectrally from D50, resulting in significant shifts in absolute color rendering, there will be significant differences between the printed image in the D50 simulator and the image on the display.
For those who care about such challenges, it is possible to address this issue by measuring the spectra of the illumination, recalculating the values of XYZ and CIELAB, and creating a new ICC profile for characterizing the printed color media. The challenge of this approach is that all profiles would have to be so created for that viewing environment, as well as databases of spot colors which typically contain lists of CIELAB values for each named color, such as lists of Pantone™ color libraries. Although this approach may well be convenient in the future, it is not convenient with current color management infrastructure which is optimized for CIELAB with theoretical D50 illumination.